This review (2020) summarizes the clinical findings of ketamine as a treatment for depression, and discusses the differences between (S)-ketamine and (R)-ketamine.

This review (2014) summarises the history of LSD research and outlines the potential applications in the future.

This review (2020) presents modern human studies into psychedelic drugs, including psilocybin, LSD, MDMA, and ayahuasca in the treatment of various psychiatric illnesses, including treatment-resistant depression, post-traumatic stress disorder, end-of-life anxiety, and substance use disorders. Safety and efficacy data are also presented, from both human and animal studies.

This narrative review (2020) evaluates the therapeutic potential of psilocybin and MDMA for the treatment of major depressive disorder (MDD), post-traumatic stress disorder (PTSD), and anxiety. The review explains the need for effective mental health treatments and highlights the lack of dose-response studies in placebo-controlled settings with a real-world clinical population.

This systematic review and meta-analysis (2020) of MDMA-assisted therapy for PTSD, found that over four RCT's (n=67), PTSD scores (CAPS-IV) were lower in the 75mg and 125mg groups (not 100mg), and depression scores (BDI) only in the 75mg group.

This systematic review (2020) looked at 10 modern studies (n=188) on psychedelics (psilocybin, ayahuasca, LSD) for the treatment of a variety of mental health disorders. The review found the studies to provide evidence for efficacy (up to months later) and safety.

This meta-analysis of nine placebo-controlled trials (n=211) showed a very large effect size (g=1.21) of treatment on four mental health conditions (PTSD, end-of-life anxiety, depression, social anxiety among autistic adults).

This open-label study (n=52) investigated the effects of ketamine (35mg/70kg) with regard to the neural correlates related to the remission of anhedonia in major depressive disorder (MDD). Ketamine infusion rapidly reduced anhedonia, a trend that was sustained for three days and correlated with increased glucose metabolism in the hippocampus and dorsal anterior cingulate cortex (dACC) and decreased metabolism in the inferior frontal gyrus and orbitofrontal cortex (OFC).

This double-blind placebo-controlled study study (n=30) with intranasal ketamine (40mg) found significant reductions in suicidal ideation (SI, 80 vs 33% remission) and depressive symptoms (MADRS) 4 hours after administration for those with SI in the emergency department.

This open-label study (n=77) examines the sustained effects of six consecutive ketamine infusions (0.5mg/kg over 40 min) in Chinese patients with major depressive disorder (MDD). Six ketamine infusions increased rates of response and remission when compared to a single-dose ketamine infusion in patients with MDD.

This open-label (naturalistic) study (n=42) with 5-MeO-DMT (smoked) found that it significantly reduced ratings of depression, anxiety, and stress. It also increased scores on mindfulness and life satisfaction. These effects correlated with higher ego dissolution and oceanic boundlessness during the acute experience.

This survey study (n=313) suggests that psychedelic experiences (MDMA, LSD, psilocybin) could reduce symptoms of racial trauma. The participant, 30 days later, slowed moderate reductions in traumatic stress, depression, anxiety, and stress.

This rigorous randomized controlled trial (n=73) found that ketamine has rapid (24 hours) anti-depressant effects (MARDS) for those with treatment-resistant depression (TRD).

This open-label study (n=24) found that repeated infusions of ketamine can sustain the rapid anti-depressant effect obtained after one infusion. Nevertheless, the effect of 6 infusions was only maintained for a median of 18 days.

This double-blind placebo-controlled study (2007; n=9) investigated state and trait anxiety, hopelessness, and panic under the acute influence of ayahuasca in long-term users. Results show decreases in hopelessness and panic, but no change in anxiety.

This double-blind, randomized, crossover, placebo-controlled replication study (n=15) investigated the effects of ketamine (35mg) on patients with treatment-resistant bipolar depression, and found rapid improvements of depressive symptoms, suicidal ideation, and subjective well-being within 40 minutes after infusion and up to 3 days after.

This open-label clinical study (n=128) investigated whether LSD (100μg) can alleviate death-anxiety in terminally ill patients by decreasing the anticipation of their illness, and found that the administration of LSD was universally well tolerated. Specific effects included a general lift of mood that lasted for 11-12 hours, acute pain relief that lasted 12 hours, decreased the total pain intensity for 3 weeks, and diminished concern over the anticipation of death for up to 3 days after administration.

This randomized study (n=80) found that participants with depression (MDD) and suicidal ideation (SSI/SI) who were treated with ketamine (IV, 35mg/70kg) have significantly lower SSI scores versus treatment with midazolam (another anesthetic). This effect consistently held up to 6 weeks later.

This analysis of an earlier open-label study (n=15) on Ayahuasca, found significant (Hedges' g = 1.75) and sustained decreases in suicidality in people with depression (MDD).

A prospective survey study (n=358) found that psychedelics may lead to significant decreases in experiential avoidance, depression severity, and suicidal ideation.

This open-label study (n=18) of group-therapy with LSD and MDMA aimed to describe the characteristics, treatment indicators, and acute effects on patients. The study makes a comparison with data from other (earlier) studies on the MEQ and ASC.

This survey study (n=51) found very large effects on mental health for special forces veterans after ibogaine and 5-MeO-DMT treatment.